Every social network needs a search engine.
You have 10,000 fans on Facebook. You feed them blog posts, promote new products through contests, and give freebies. Your user engagement levels are high! But wait, how did those users (which became instant fans) knew about your Facebook page again?
According to the findings of analytics tool for Facebook called PageLever, search engines are major traffic drawers for Facebook pages. The study analyzed 1,000 pages that have at least 10,000 fans. PageLever's study showed that 34% of all external referrals are from search engines. Google lead all engines with 27.57% of all external traffic that leads to Facebook pages. Google sends more than 10 times the traffic than Bing which partnered with Facebook to enhance their social search conquest.
However, this means that 27% of pageviews doesn't come from Google, but 27% of external referrals are from Google (Social SEO is still quite complicated for some, isn't it?). Facebook reports both pageview-internal-referral-sources (users coming from elsewhere within Facebook) and pageview-external-referral-sources–these are just search-engine-percentages of total-external-referrals.
Aside from search engines, one of the most notable traffic drivers is YouTube which beat the overall referral percentage of Bing. With Google enhancing content curation on Google+ and utilizing the +1 button, expect Facebook to enhance its user interface to achieve higher internal referrals more than external referrals from Google.